Almost every homeowner at some point asks the question, “What are the best energy improvements I can make to my house?” The answer to that very important question is “it depends.” It depends on the climate (cold, hot, or mixed; humid or dry), the condition of the house, and what specific problems the homeowner is having. In no particular order, here are some of my favorite energy upgrades, including some of the issues that they “depend” on.
1. Insulate ceilings and floors: In all climates, attic insulation is a good improvement to do, but it works much better if you seal up all the air leaks at the same time. This usually means pulling existing insulation away from all the walls and caulking or foaming all the holes for pipes and wires, sealing up recessed lights by building a fireproof box over them, caulking around ducts, and especially, sealing up chases and dropped soffits – those sneaky holes that allow air to flow around the insulation. See the DIY guide from ENERGY STAR for good information on attic sealing.
2. Seal attic knee walls: If your house has a bonus room over the garage or other short walls in finished attic spaces that separate living space from the attic, those are called knee walls, and they are very likely a big energy suck. Knee walls need to be insulated more than regular walls and have a solid air barrier on the attic side. Wall insulation needs a separate air seal to work properly, and when you have that 150+ degree (it happens under poorly insulated roofing in hot climates like Atlanta) attic on one side of a wall without an air seal, it doesn’t do a good job of keeping the heat out. You also need to install blocking from the bottom of the wall to the ceiling below to cut down on air movement. This is one of those “it depends” improvements. If you don’t have knee walls, then you don’t need to improve them. If you have them, then you really need to make sure they are done right.
3. Seal your ducts: Most HVAC systems have very leaky ducts. HVAC contractors will often sell you a new high efficiency furnace and air conditioner, convincing you that you will save a lot of energy. But when that new, efficient equipment is attached to crappy old ducts that leak half or more of the air to the outside or the attic, all that high efficiency equipment won’t work very well. Make sure that your ducts are sealed with mastic – a white or gray gooey mess that does a great job of cutting down on leaks. Don’t ever use duct tape; it just doesn’t work. The foil tapes that are designed for sealing ducts work a little better, but not nearly as well as you want them to. It is really critical to seal all the metal to metal and metal to flex duct connections. Don’t bother to seal up the insulation unless you have also sealed everything underneath it.
4. Shade screens on windows: If your house gets too hot from sun shining in west, south, and east facing windows, give shade screens a shot. Available from several maufacturers including Phifer, they replace regular window screens and cut out between 70 and 90% of the sun’s heat. If your house doesn’t overheat, then this one isn’t for you.
These are just a few of many things you can consider doing to improve your house and make it more healthy and efficient. Consider having a professional energy audit from a home performance professional to get more ideas of things to do.